I surgest you lern some more by yourself first.
With your pressent knowlage you would usaly only get offered to write documentation. or proffreading.
Ofcourse, by writing good documentation one need to lern some programming.
But I still surgest you try to lern some more by yourself. Ther is MANY toturials out ther for varius programming languages.

I have never used sourceforge "help wanted" or anything like that.
If you want to help, I surgest you find a project that intrest you, and contact someone ther, offering what help you can give.